We understand your concern and are here to pray with you and provide biblical guidance. First, let's address the issue of your stepmother's boyfriend spending the night. According to biblical principles, sex before marriage is considered fornication. The Bible tells us to "flee sexual immorality. Every sin that a man does is outside the body, but he who commits sexual immorality sins against his own body." We see that your stepmother is not living in accordance with God's will in her life by allowing her boyfriend to spend the night. This is a serious issue that needs to be addressed.
Let's also remember this more general admonition against behavior that first lead to these situations since typically a sexual relationship does not instantly start but is built up to, Romans 13:13-14 Let us walk properly, as in the day; not in reveling and drunkenness, not in sexual promiscuity and lustful acts, and not in strife and jealousy. But put on the Lord Jesus Christ, and make no provision for the flesh, to fulfill its lusts. (WEB)
We can't be sure if your stepmother is truly a devout Catholic. This is a spiritual struggle she is facing. Since mixing religions is also a sin, it is worth pointing out that even Jesus did not condone someone adding to their faith. Jesus did not ask the apostles to remain Jewish and Christian, there are not different levels or different religions to get to God through Jesus, Jesus is pretty clear about this and we are not to order our religion and celebrations to match that of others, as it may lead others astray on this point, it is also clear that the apostles never endorsed the maintaining and mixing of religions.
Galatians 1:6-9 I marvel that you are so quickly deserting him who called you in the grace of Christ to a different "Good News"; and there is not another "Good News." Only there are some who trouble you and want to pervert the Good News of Christ. But even though we, or an angel from heaven, should preach to you any "Good News" other than that which we preached to you, let him be cursed. As we have said before, so I now say again: if any man preaches to you any "Good News" other than that which you received, let him be cursed.
Your stepmother should be encouraged to pursue a godly marriage if she is serious about her relationship with her boyfriend. Meanwhile, pray that she finds strength and conviction to resist temptation and live pure. Additionally, it is important to address that we only have access to God through the name of Jesus Christ as it is only through the name of Jesus that we can be saved, there is no other name. Acts 4:10-12 be it known to you all, and to all the people of Israel, that in the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead, in him does this man stand here before you whole. He is 'the stone which was regarded as worthless by you, the builders, which has become the head of the corner.' There is salvation in none other, for neither is there any other name under heaven, that is given among men, by which we must be saved!"
Let us pray together:
Heavenly Father, we come before you in our time of need, lifing up Osvelis and his stepmother to you. Lord, we pray that you would convict your stepmothers heart and help her to see that life and her actions that may be deemed as fornication in marriage is not your will and not your way in her relationship with her boyfriend. Lord, help her to understand the importance of living pure. Lord, we pray for salvation by the name of Jesus Christ if she is not claiming that for herself as there is no other name under heaven by which we can be saved. Lord, guide her steps and help her to see that marriage is a lifelong commitment between a man and a woman. May she offer herself to her future spouse as you intended. convict her in regards to church attendance and closeness to you . Help Osvelis to communicate his concerns respectfully and with love as one would through the fruit of the spirit, and provide Osvelis with Bible verses to share with his stepmom generously. Lord, we ask for your guidance and wisdom in this situation. May your will be done in their lives. In Jesus' name, we pray. Amen.
And he said to him, "You shall love the Lord your God with all your heart, and with all your soul, and with all your mind.' This is the first and great commandment. And the second is like it: 'You shall love your neighbor as yourself.' On these two commandments the whole law and all of the prophets depend." Matthew 22:37-40.
May the above scripture encourage you to speak to your stepmother with love and kindness, while also holding firm to biblical truths. We can love others while holding to the truth of the word of of God. In the Jesus' name we pray. Amen. We believe that the Christian lifestyle requires love and encouragement but also to be rebuke those with a love of the world.